Production of hexaorganodisilapropanes



Patented May 16, 1950 A I UNITED STATES PATENT OFFICE PRODUCTION OF HEXAORGANO- DISILAPROPANES John T. Goodwin, Jr., Pittsburgh, Pa., assignor to Dow Corning Corporation, Midland, Mich, a corporation of Michigan No Drawing. Application April 20, 1948, Serial No. 22,254. In Great Britain July 1, 1947 zoo-448.2)

methyl silane. It may likewise be prepared by reacting chloromethyl dimethyl silicon chloride with a methyl Grignard reagent. Other materials of this type may be prepared by reacting chloro methyl silicon trichloride with any desired Grignard reagent to introduce three organic radicals on each silicon.

The hydrocarbon radicals in each of these types of compounds are preferably aryl such :as

by Kipping. The present organosilicon industry phenyl, or alkyl such as methyl or higher alkyl, is based upon the siloxanes which are materials for example, octadecyl. in which the silicon atoms are linked through The tricrgano silicon halide and the triorgano oxygen atoms. There has been some mention in ehlormethyl silane may be contacted in liquid the literature heretofore of organosilicon halides phase with the alkali metal by a variety of specific Containing a p u y of Silicon atoms n which means. Thus a mixture of the two reactants may the silicon atoms are linked by large divalent be mixed with the alkali metal. For this purpose organic radicals and the remaining valences of it is convenient to suspend the alkali metal in a the silicon atoms are satisfied by ch orine. liquid vehicle non-reactive with respect to the Objects of the present invention are to produce alkali metal to which suspension the mixed reorganosilicon compounds in which the silicon actants are added. Alternatively, the alkali metal atoms are linked through methylene bridges. may be added to a mixture of the 2 reagents. By In accordance with the process of this invenanother preferred procedure the alkali metal may tion, compounds of this type are produced by be mixed with the triorgauo silicon chloride and act a cl io lli g d Ola 11260131; l fc t 'iz 9v the mixture then mixed with the triorgano chlorcompound 0 e ype 3 i 2 y con ac ing methyl gilang thetlatter with the alkali metal in the presence The ti hgreof occurs readily under t- 0f he former compmmd- The Various B73 in mospheric pressure at room temperature. Elethese reagents represent monovalent hydrocarvated temperature may be employed by increasbon radicals bonded toksilicon by carbon to silicon ing the pressure sufliciently to maintain at least d c a all Y radicals, ins @1106 a portion of the reactants in liquid phase. The methyl d octadecyl, and monocyclic alyl ireaction is sufiiciently rapid that elevated temal f r Instance phenyl and oly By t111s perature may also be employed by adding the two m d co p of the abOVe mdlcatad type reactants to molten sodium in suspension. 7 are produ d Thus it is to be seen that Whereas the reactants Th15 15 not m ajccordfmce with expestatmn are either non-reactive with sodium or will react Smce th i l'f 232 ;gi i gffiifis g gg individually to produce undesired materials, tll g c111 W1 9 c Y two materials will reac wi sodium 0 yie connectfion w the trimethyl chloride compounds which contain the fundamental strucairfiarctlon mlght be Qxpected yleld hexameihlfl ture zsiCl-lzsis. Compounds which contain this dlsllane t has been found that g 40 structure are of special utility as lubricants and Smcon chlonde does not react Wlth as hydraulic fluids. In certain instances, they The triorganosilicon halides which are e-mi htewlse be .employed for flectncal uses as insulating materlals. The particular and outployed are those which contain 3 hydrocarbon t f thi 1 f d radicals bonded to the silicon by carbon to silistaedmg proper y 9 S 5 compoun 5 15 con bonding and in which the halogen is either their extreme chemical stability. Thus when the chlorine or :bromine. Compounds of this variety Pydrocarbon radlcals Whlch are lmked 9 the have been described frequently in the literature. 51.119011 atoms are methyl groups, wh reby insta- The material reacted with the triorgano up bility of the organic radicals is avoided to the con halide has the general formula RaSiCI-lzX 50 at st ext nt. th compound is stable v n in where X is bromine or chlorine, and R. is a monothe presence of concentrated sulph acid, nitric valent hydrocarbon radical bonded to the siliacid and sodium hydroxide. This is a contrast con by carbon to silicon bonding. The compound to the equivalent compound in the siloxane series, of this type in which R. represents methyl may be hexamethyldisiloxane in which the siloxane linkprepared if desired, by the chlorination of tetraage is hydrolyzed by any of these reagents.

The following examples illustrate the method of the present invention.

Example 1.-61 parts by weight of (CH3) sSiCHzCl 55 parts of (CH3)3SiC1 and 100 parts of hexadecane were placed in a reaction vessel and heated until refluxing occurred. 23 parts by weight of metallic sodium were added slowly in small pieces while stirring the reaction mixture. The reaction proceeded slowly at first due to the low reflux temperature. As the reaction occurred and the reactants were used up, the temperature rose and the reaction rate increased. The prod ucts distilled from the reaction mixture until the boiling point indicated that hexadecane was starting to be distilled. The distillate was redistilled whereby 52 parts of a material boiling at l32.2 C. at 740 mm. were obtained. This mater'ial was found to be (CH3)sSiCHzSi(CH3)s. The yield was 63.4 percent. The properties of this product are as follows:

vvvv

w on 3 Percent Si Percent G O/si Viscosity (lglgolar refraction based on paper by E. L. Warrick, JAG S, 68, 2455 Example 2.69 parts by weight of metallic sodium and 400 parts toluene were placed in a flask and heated until the sodium melted. 183.8 parts of (CH3)3SiCHzC1 and 162.8 parts of (CH3) 351C! were mixed and added to the flask. The product was cooled and filtered, washed with toluene and distilled. There was obtained by this distillation 42.5 percent yield of (CH3) :aSiCHzSi (CH3) 3 That which is claimed is:

l. The method of preparing compounds of the type RzSiCI-IzSiRs in which R, is a member of the class consisting of alkyl and monocyclicaryl radicals which comprises reacting a compound of the type RaSiX, in which X is selected from the group consisting of chlorine and bromine, with a compound of the type R3SiCI-I2X by contacting the latter in liquid phase with an alkali metal in the presence of the former compound liquid phase.

2. The method in accordance with claim 1 in which the alkali metal is contacted with a mixture of compounds of the types R3SiCH2X and RsSiX.

3. The method of accordance with claim 1 in which R represents methyl.

JOHN T. GOODWIN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

Goodwin: J our. Am. Chem. Soc, vol. 69 (Sept. 1947) page 2247. 

1. THE METHOD OF PREPARING COMPOUNDS OF THE TYPE R3SICH2SIR3 IN WHICH R IS A MEMBER OF THE CLASS CONSISTING OF ALKYL AND MONOCYCLICARYL RADICALS WHICH COMPRISES REACTING A COMPOUND OF THE TYPE R3SIX, IN WHICH X IS SELECTED FROM THE GROUP CONSISTING OF CHLORINE AND BROMINE, WITH A COMPOUND OF THE TYPE R3SICH2X BY CONTACTING THE LATTER IN LIQUID PHASE WITH A ALKALI METAL IN THE PRESENCE OF THE FORMER COMPOUND IN LIQUID PHASE. 